As is well known, in the production of manufactured products, it is typical to enclose various components of the manufactured products within a protective housing. Such housings typically have been assembled in numerous ways, such as by mechanical fasteners, soldering, brazing, and/or welding.
Such prior art housings and techniques for assembling such housings possess inherent deficiencies when utilized in the assembly of modern, heat-sensitive components, such as electrical or microwave devices. For instance, it is customary practice for modern, heat-sensitive microwave devices to be enclosed within a sealed housing to protect the microwave devices throughout prolonged use. Typical of such microwave devices is a microwave series feed assembly consisting of a main feed line coupler and auxiliary coupler elements which are assembled (or packaged) together with numerous heat sensitive dielectric insulators, all of which are enclosed within an elongate aluminum rectangular conduit. Heretofore, it was customary practice to enclose such sealed microwave devices in an aluminum rectangular conduit by use of threaded fasteners, solder, dip brazing, arc welding, or laser welding to attach and seal a cover to the conduit or chassis after component assembly. Such prior art fastening or attachment techniques, however, have proven infeasible when new technology requirements dictate that the enclosure be lightweight, low cost, contain heat sensitive components, and/or be extremely long in length.
In this regard, the prior art use of mechanical fasteners, such as threaded fasteners, requires additional material to be provided on each side of the housing of the device to accommodate such mechanical fasteners. Further, such mechanical fasteners must be spaced at very close intervals to achieve the required structural or electrical performance characteristics of the device. The use of such additional material and fasteners necessarily results in a device having increased weight and size.
The prior art soldering assembly techniques require nickel and tin pre-plating of areas to be joined prior to soldering. Further, the heat required for proper soldering applications oftentimes damages heat-sensitive components contained within the microwave device. Further, the structural integrity of long microwave devices is suspect when the soldered joint is exposed to dynamic environments.
Similarly, the prior art dip brazing assembly techniques require that the entire housing be exposed to very high temperatures, i.e., approximately 1,000 degrees Fahrenheit in some cases, to achieve the desired integrity of the brazed joint. Such high temperatures typically anneals and distorts aluminum enclosures and further may damage the heat-sensitive components contained therein. Prior art arc-welding techniques additionally result in heat degradation similar to that of the dip-brazing process. In addition, arc welding requires a thicker wall section of metal be present in the weld area to eliminate possible burn-thru at the arc-welding site, which additional material increases the overall weight of the assembled device.
Finally, the prior art use of laser welding in the assembly process concentrates heat in a very small area so that thermal degragation of the microwave components is normally quite small. However, laser welding has been a slow and expensive process which typically renders it a cost ineffective assembly solution in many potential applications.
Thus, there exists a substantial need in the art for an improved method of assembling heat-sensitive components, such as microwave devices, within a sealed housing which is conducive to low cost, mass production techniques, and which additionally accomplishes assembly without generation of excessive heat that could degrade the heat-sensitive components disposed within the assembly.